The present invention relates to devices or apparatus which are used to heat fluids and, more particularly, the present invention relates to a centrifugal device for pumping and heating fluids including a cylindrical rotor featuring a number of bores arranged in a certain pattern where fluid is subjected to relative motion thereby producing fluid heating.
The prior art designs of known devices such as stirrers, rotors and scrapers make use of the transfer of kinetic energy to a moving fluid by means of a rotary member. Such devices result in heat generation of a fluid which is due to phenomena, for example:
(1) A water hammer, which is a pressure increase in a pipe, caused by a sudden change in fluid rate or by holding up fluid in the flow;
(2) A shockwave, which refers to a completely developed compressional wave of great amplitude, through which density, pressure and rate of the particles drastically change; or
(3) A fluid friction, wherein the fluid flow mechanical energy is converted into calorific energy.
In order to provide heat generation in the fluid, the prior art devices are necessarily mechanically complex devices which require extensive maintenance and servicing due to wear. One example of such a device is U.S. Pat. No. 3,198,191, issued to Wyszormirski, where rotary vanes drive the liquid against cavities in the casing of the housing. The resultant stirring and friction cause the fluid to be heated. In U.S. Pat. No. 4,143,639 issued to Frenette, a rotary rotor and a casing are described, which structure friction heats the lubricant. Also, in U.S. Pat. Nos. 4,483,277 and 4,501,231 issued to Perkins, the same principle of a rotary rotor is used for generating heat by friction. Also, in U.S. Pat. No. 4,779,575 issued to Perkins, rotary rotors are described having fluid inlets in the center thereof with nearly radial bores extending to the surface thereof, wherein the restriction bores produce heating of the fluid by way of friction.
In U.S. Pat. No. 5,341,769 issued to Poppe, a rotary rotor is described having nearly radial bores for causing friction through outlet restrictions. The liquid is driven by a centrifugal force to produce heating of the liquid. Also, in U.S. Pat. No. 5,188,090 issued to Griggs, a rotary cylindrical rotor featuring surface bores produces turbulence within the casing cavity. The bores cause shockwaves and the fluid completes a cavitation process or the formation of bores or cavities in a liquid. Usually, the prior art devices require assistance, which means that the fluid to be processed is required to have a certain inflow pressure. Additionally, such prior art devices generally do not increase the fluid outflow pressure.
In the development of the present invention, between the rotor and the casing there is a typical Taylor-Couette fluid flow created. This flow has been the subject matter of several studies related to the development of normal instability due to turbulence when a fluid rate increases excessively due to an increase in the peripheral speed of the rotor. When the rise in the Reynolds number exceeds a critical value, instability of the fluid occurs.
It is an object of the present invention to provide conditions and structure for developing fluid internal friction, without exceeding a laminar boundary of the fluid.
It is another object of the present invention to improve upon such prior art devices, which results in a constant rotary movement that creates internal friction and a centrifugal force in the liquid based upon the rotary speed of the device. The higher the rotary speed of the device, the higher the temperature and the centrifugal force. Such conventional treatments have a drawback arising from the fact that when rotary movement is created in a liquid, there is a rate limit that may be reached before the fluid is inevitably exposed to an instability created by vortex formation. As the rotary force increases, the vortexes (unipole, bipole, tripole) finally destabilize the fluid thereby resulting in a limited temperature and a limited fluid pressure.
To overcome the drawbacks of the prior art structures, in the present invention there is a proposed rotor design, which is preferably a flattened, cylindrically shaped rotor featuring front bores with an optional cluster of bores on the cylindrical peripheral wall. The fluid flow is maintained within the laminar boundary before flowing into the instability of the Taylor-Couette flow, which is due to a rise in the fluid rate and a rise in the peripheral speed of the rotor.
The device, in accordance with the present invention, comprises a housing having a fixed casing surrounding an inner cavity. Positioned within the inner cavity is a cylindrical rotary rotor or member structurally arranged to rotate therein. On the rotor""s front rotor""s face, opposite the fluid inlet, the rotor facing features a number of identical hollows, recesses, irregularities or bores symetrically positioned thereon. It is preferred that five recesses in a regular pentagonal pattern be positioned on the rotor""s front face. These recesses may be complemented by a cluster of bores or recesses, preferably three in each cluster on the cylindrical peripheral wall of the rotor.
Accordingly, in accordance with the present invention, the critical value of the Reynolds number is higher than those achieved in prior art devices. Thus, the device of the present invention may be smaller in size than the prior art devices. With the present design, the device achieves higher heating temperatures as well as a higher centrifugal force.